-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 MX4eEMf4xY6IOJB9jeAM63v6vQrmTMLKbaksGo0m3Uc5oE97hLO2brUA6du15EEy
 EJoPnKv3tpG+tFiHAZCfXg==

<SEC-DOCUMENT>0000895813-10-000090.txt : 20100422
<SEC-HEADER>0000895813-10-000090.hdr.sgml : 20100422
<ACCEPTANCE-DATETIME>20100422155454
ACCESSION NUMBER:		0000895813-10-000090
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100420
FILED AS OF DATE:		20100422
DATE AS OF CHANGE:		20100422

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROWE JOHN W
		CENTRAL INDEX KEY:			0001067838

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-05965
		FILM NUMBER:		10764524

	BUSINESS ADDRESS:	
		STREET 1:		950 N MICHIGAN AVENUE
		STREET 2:		#3306
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60611

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			NORTHERN TRUST CORP
		CENTRAL INDEX KEY:			0000073124
		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
		IRS NUMBER:				362723087
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		50 S LASALLE ST
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60603
		BUSINESS PHONE:		3126306000

	MAIL ADDRESS:	
		STREET 1:		50 S LASALLE ST
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60603

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	NORTRUST CORP
		DATE OF NAME CHANGE:	19780525
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-04-20</periodOfReport>

    <issuer>
        <issuerCik>0000073124</issuerCik>
        <issuerName>NORTHERN TRUST CORP</issuerName>
        <issuerTradingSymbol>NTRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001067838</rptOwnerCik>
            <rptOwnerName>ROWE JOHN W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>50 SOUTH LASALLE STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60603</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2010-04-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1625.43</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10272.68</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents stock units payable automatically on a 1-for-1 basis in shares of the Corporation's common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Paul A. Bernacki Attorney-in-Fact for John W. Rowe</signatureName>
        <signatureDate>2010-04-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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